The retrospective study for evaluation of post-operative bleeding was performed on 403 cases of tonsillectomy and/or adenoidectomy for one year. The results obtained were as follows ; 1) Total number of post-operative bleeding were 10 cases(2.48%). The primary bleedings were 6 cases(1.49%) and secondary bleedings were 4 cases(0.99%). 2) In sex incidence, 8 cases were male and 2 cases were female. In age distribution the highest incidence was in the group of 21-25 and followed by group of 26-30 and 16-20. 3) There was no specific difference in post-operative bleeding incidence by operators, as seasons and types of anesthesia. 4) In 10 cases of post-operative bleeding, the number of post-tonsillectomy bleeding were 8 cases and post-adenoidectomy bleeding were 2 cases. 5) In bleeding control methods during operation, the highest incidence was in compression method(25%) and followed by ligation of vessels(2.86%) and electrocoagulation(2.70%). 6) In 16 cases which had abnormal pre-operative laboratory findings(2 cases of prolonged coagulation time and 14 cases of abnormal count of platelet), no post-operative bleeding case was noted. 7) In pre-operative and post-operative systolic and diastolic blood pressure, pre-operative values for the bleeders did not differ from those for the total population, but post-operative values were significantly higher for the bleeding group.